Re: [PATCH 1/9] linux-user: Diagnose incorrect -R size

[Peter Maydell]

On Fri, 17 Mar 2023 at 14:46, Richard Henderson
<richard.henderson@linaro.org> wrote:
>
> On 3/7/23 02:17, Peter Maydell wrote:
> > It looks like we (inadvertently) broke "-R 0 means turn off"
> > in 2019 with commit dc18baaef36d95e5; prior to that the
> > 64-on-32 default was set by the initial value of the global
> > variable and could be overridden on the command line. After
> > that we ended up doing the default-value stuff after the
> > command line was parsed instead.
>
> (Not 64-on-32, but 32-on-64.)
>
> I don't understand how 32-on-64 would ever work without reserved_va.  The 
> host kernel
> would otherwise place mmap blocks anywhere it chooses, which may not be 
> within 4GB of any
> given guest_base.

I think most of the use cases weren't doing mmap of any
kind. The gcc test suite is one example of that.

-- PMM